More workers have been brought in by Gatwick airport and its baggage handlers in an attempt to avert further embarrassment after passengers were left without their luggage over the peak holiday weekend.

Swissport, the handling firm which failed to cope with an influx of late-evening flights, has bolstered its 1,500 staff by 40 – but this was too late to save it from being axed by one airline, Monarch.

Gatwick will also deploy 60 extra staff over the coming weekend to help move bags and aid customers if needed, although security and insurance rules prevent its staff from unloading planes. A spokesman said: "This is a contractual arrangement between airlines and their agents and there is little that the airport can do to sort it out."

He added: "We have established service standards for our own staff, as well as for ground handling agents, who supply services to airlines such as unloading baggage from aircraft and delivering them to the baggage hall.

"Recently, Swissport has failed to meet these standards. Although bags are being delivered on time for 95% of flights, this is not good enough. This has been frustrating for passengers and we are disappointed with the recent arrival baggage service."

He added that there were currently no problems with loading outbound bags and no question of people flying abroad without luggage.

In an embarrassing debacle for an airport currently pressing its ambitions to match Heathrow as a two-runway London hub, luggage from incoming flights last weekend failed to appear on carousels four hours after arrival. One passenger, a Team GB paralympian, was left without his wheelchair in the baggage reclaim hall. The problems peaked on Saturday night, keeping returning passengers at the airport until the early hours of Sunday.

Swissport denied that zero-hours contracts had contributed to the problems. A spokesman said the firm employed only 50 people on such contracts at Gatwick – at the workers' own request because it suited their lifestyle.

Swissport said the delays were mainly due to "a high level of off-schedule flights that we were unable to accommodate". A spokesman continued: "Nothing that has happened during the past week gives an indication that this weekend will change the service given over the past week. The summer peak season puts pressure on all baggage handling companies."

Gatwick's biggest airline, easyJet, uses another baggage handling firm. Around 27 carriers including British Airways, Thomson and Thomas Cook use Swissport at Gatwick.

Monarch Airlines said it would not comment on contractual arrangements, but is understood to have had enough and will not be renewing contracts at Gatwick or Manchester. Monarch said: "We are working closely with Gatwick airport and our ground handling agent to improve service levels for customers flying with us."

British Airways said: "We have been given no reason to expect any issues this weekend at Gatwick, either from the airport authority or Swissport. We will continue to work with Swissport to improve the levels of service to our customers."